The prior art is replete with numerous examples of sheet metal cutting and forming devices which have been fabricated for various purposes including specific operations such as cutting, perforating, embossing, crimping, and forming to name but a few. As a general matter, conventional sheet metal cutting and forming devices are typically fabricated utilizing numerous reciprocating presses. In this regard, material to be worked is placed within a press; positioned in a stationary location over a die; and thereafter the press, which is usually mechanically operated, is closed thereby forcing a second die into contact with the material being worked. Upon completion of the perforation or other forming step, the press is opened and the material being worked or other work piece is removed and a new work piece is later inserted; or the material being worked is indexed to a new position such that the process can be repeated.
Various solutions have been suggested for increasing the speed of operation of such devices. For example, in U.S. Pat. No. 4,732,028 the teachings of which are incorporated herein, one prior art solution included the use of a so-called flying shear or die which is used with a strip which is moving continuously. In this system, the die is accelerated to the speed of the strip, and the press closes while the die and strip are moving in unison. The die then opens and returns to its starting position. Typically the punching, forming and shearing of continuous material utilizing a device such as this is limited to a line speed of about 250 feet per minute.
The prior art further discloses various rotary machines which are useful in shearing or forming web-like material. However, in the use of such devices it is well known that flat dies used in conventional reciprocating presses do not operate in such devices. Still further, considerable problems are encountered in the use of curved dies. In this regard, many prior art references teach and acknowledge that curved dies, while they will work on various materials, will often cause deformation and distortion of a work piece.
In addition to the foregoing difficulties, many products that are fabricated from web-like material such as sheet metal, and the like, often require that different sized apertures be formed in various locations in the web in order to form a resulting work piece. Examples of such work pieces such as metal structural members, are illustrated in FIGS. 1A, 1B and 1C, respectively. As will be appreciated from studying those Figures, the positioning of appropriate dies in the correct locations and the proper distances presents difficulties in the manufacturing process. Typically, the machines which are useful for this purpose are very long in length, and the resulting control systems necessary to control the speed as well as the positioning of the web material relative to the various rotary presses needed for such end products presents assorted difficulties.
Therefore, a new and improved web forming machine which addresses these and other shortcomings attendant with the prior art practices and apparatuses utilized heretofore is the subject matter of the present invention.